DE-A 3733033, U.S. Pat. Nos. 7,053,129 and 3,925,264 disclose a process for preparing aminomethylated bead polymers, in which phthalimide is converted in the presence of formaldehyde and in the presence of bases and swelling agents, especially in 1,2-dichloroethane, to N-hydroxymethylphthalimide, which is converted in a further step under acid catalysis to bis(phthalimidomethyl) ether. This ether is reacted in the presence of Friedel-Crafts catalysts, especially in the presence of strong acids, with the bead polymer to give the phthalimidomethylated bead polymer. The phthalimidomethylated bead polymer is then hydrolyzed under alkaline conditions to give the aminomethylated bead polymer.
A further process for preparing aminomethylated bead polymers is known from U.S. Pat. No. 4,232,125 and PCT/EP2014/067109, in which phthalimide and paraformaldehyde and the bead polymer are converted, likewise in the presence of 1,2-dichloroethane as swelling agent, together with sulphuric acid as Friedel-Crafts catalyst, in a one-pot reaction in which the carbonium ion of methylphthalimide is formed as intermediate, to the phthalimidomethylated bead polymer. The phthalimidomethylated bead polymer is then hydrolyzed under alkaline conditions to give the aminomethytated bead polymer.
A disadvantage of the aforementioned processes is that the yields are unsatisfactory.